SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee69805bdd261d7da582a79cb8a8c63ddacc13235162e379a2953834d113c154' 
  AND token = 'UYr7FL1Nkzd8En71AfNRIwBieL0mKAwhEpNWDYuVyE0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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