SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c45a55e39f645df191f3a4a938d08bf89955564e9708d2e1aff1439b22e8b0ab' 
  AND token = 'ufRBJuU1LfcaAoCo0hhv7MA3GhDmYn87p7M2esWlmw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}