SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6a87a2650ba8ff27a60728f255c155ff743780d12de09718d7373cd9224df28' 
  AND token = 'GI0nqqrTh91lBpuKlatcL3Dn81OjGFdcbj+YyPczkQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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