SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '363c5cc44500012224815bb942dbf2b742b81ccee6ce8ecc820136987e7308ea' 
  AND token = 'vmxsXQq5ptsjmZ3JVMji+JwTdc4eQtvs4WY5up81zfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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