SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0b5fb9113426b92da344a51eb977f3bdc897bbe6c20f9280da4e1c716ab8f3a' 
  AND token = 'OsNG+4ZWY+Ef4OrUK6t1UfwBy//J1SYjFpupGuwx1co=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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