SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d97dfa578fa5df25c9c0b79111d436fb182efe54d043af83a728a8e05253469' 
  AND token = 'ZjhSCT/k2hkllzb2kQIvGSQGCFtIy5ctdydz9uGeIo4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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