SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '644433b7051a7f9da1e93c0cf9a552da9c32f2d19b6b11cd15953ff751adef8b' 
  AND token = '88YChoPgyTpjb2mkSPRvEupLCNK/U8rZXSFsdHHABiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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