SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2f63a81cabfbaa398b4623525f99e0b7775ca874779c8e23571eb859d2a59f8' 
  AND token = 'j2lNIe1IAY96kgih7T4Ge/X45DDGoXz7Jk5WxdHm4hM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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