SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c137ff2f435cdf7ae37c6a9c1e24f816c78cf05a19422fb7c5e24dd3b391879' 
  AND token = 'RVgj+BQoVcWio/WHbwYjHNVPosMjGhinh341YcnKG2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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