SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f49636902fc9acc81d428585b6cda3105e084a92b208434cf70d246f7e3883a2' 
  AND token = 'BzK+QmMaMwp45Xn5ouzDTx1PDZsEPeQUygE2ijYTyHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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