SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '74a915a0fd884e191fc1eca535f1436408404b2070ef00064db6596d686d1240' 
  AND token = 'VmLb2+gzB3i6XXX5nTj6zgKkoA1nklc+jPRgRF+wlvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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