SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dce848d1bd4cb0ed5273e3ec93c87cf08987ad12ebc0d01bd58a3f8d03d6f20e' 
  AND token = '3N1aG4R1TN/4x0m2yZWePrbCxUQ6Jo59HodlX6Spv8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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