SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9f6f71fa86217d425cf6033a230657ec0388bec7f44220367644525e2a8f04d' 
  AND token = '6hoLFMX/Q9zuMh6YLdvCj/gmt6ZvOzYDeggM+svdNnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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