SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee6b53e4234625555a0d3a1f9827ba787a8c7b790b529645017a02ef9de37b45' 
  AND token = 'zehjqGdOogLerImbOMLX1vt2P+tZhWfDBbrtbbAR4yY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}