SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4385b814750e6c58983bde73d8217d7946fb1bc76053542bb4fe0c9c516c4329' 
  AND token = '9X75BpybcWyWfReApPSfPYJS7UCxnn+JEAJV9MyY7fs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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