SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab76672f57d28b4d1afca2585c442198e406eb9c1e0ddd004c158aadef97f565' 
  AND token = 'OJQkIwDqV5Pg/VOVmxug2tSHR0hhL5PROcJX82UvyV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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