SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55e0768e54d82befdb6318ea8b0cbbcb20ca8d005f297b84bd4dab3980c2f554' 
  AND token = 'D/DGd0xwDBGvaNe87g5j6jNw5d/RMwR2V1eqEO4oCNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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