SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3875b5c252745ecd67f5f0e408a0bb707e411a6b8031f95965e223259bba5d3a' 
  AND token = 'fZyQ6Jih67/s7ICvX7uUQnDTlkaVWG2v/YBGFwYK+YU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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