SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '757b72c3c306d298e2e7a7d8b17256ffc4a5d820f95a2b363ebbbb00757c7bb8' 
  AND token = 'ghbC9IOqmm8EJyp425aAj2CfzUprhCcDoGhnbPwRy0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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