SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a395a2eb6f7779ca8dea2ff1d42367b7867e21113b608ed4ac5a02dfa501c4f2' 
  AND token = 'iEY5fodXN3LOeUX3fhtPEozB4UPfeqY26wLgqSeYLS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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