SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff7b032104eaa53a6dcc854b63ffe5141fe9863c7464e3bf281e2a1d32f5759c' 
  AND token = 'AVe7L5FhumlEhPvpVCmBJRvxZIDjHDCxnhScim2Z6Pw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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