SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f725bf61025137e825d5fb5d483c5a57b3631e4341f3bec4313238950a1092a6' 
  AND token = 'KxPMnTkR5+3QNERVglC0o+BX6Qk2F7JVDgW9gdlkvD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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