SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '36b9c13e88dbae06687baac8c30c88bc5e60f51bc2a5e4c38e6eb395b2716ac3' 
  AND token = 'RhR+3JG96hpuMLgPWjYZuF1K1aQAiaRSe7sn1usIO/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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