SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2b5528c6ce916c13c70f5725cd6680328c89262ea32d8bbf1f0c4e8b86dbd49' 
  AND token = '84isrbZvxhQ7bx2Nfn8j/KJE5q6SHQ/cmO2ZWFfxUlw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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