SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4184976aa70ad5b34e22897617f2ba299ceaf9946581abfd3d2232987ff1e4fb' 
  AND token = 'xSMLZdxGVEG8FV78faDskX5lKwlSH126xK3RqJK+rK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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