SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b48d5c6156ce9dc5c935dcaeb0bace46dfd776badfda23d0a516a7f4508e5feb' 
  AND token = '2PJMAFobL+GM4Sh1S+xxurpkXBHY8KgGt2Bi6L8gn1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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