SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fc357a4ea174c874973af75ac1e636682b45f30b49ae759a19aea0defb8843f' 
  AND token = 'RhSU61GoTAOFFK1ps1qtm36dQvJoizoLQiPXZNuvGAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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