SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a636c018a55cc0ffdcbab0951921833bc736582e57aa14c7c34e20c172dea8a' 
  AND token = 'zSG2runp/naqw98Ff4Zgr7mK439Ut3U7VsmxRz2kSYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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