SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b17b06a8d45b0cb14d33628a8d4179365aa53f7cee5ee50460de9b864a38e1ec' 
  AND token = 'PoLcWkklLONKAItSlJFQfJdpokkGlspEqYMbcL6YKCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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