SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3df4eba32b0b138b60c2b3946190a196ab7e11f1325759d3051cd22b7b68d97e' 
  AND token = 'hhGAtwvQpv/6vofUGoJdFBMAuqan9w5On/TgGNBiB54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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