SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1029309d0347abd9a3c76d336a260e4cffbecfd66c9420b53389970375e0187' 
  AND token = 'WAGItpm9iX6hFMK2L9oSvnq+f49KdLEjwvbDOwhocvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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