SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d340d5aa157bc25d45f97b79532d3e855f004964f36b1aa4ae33705e4bf18ab' 
  AND token = 'bLWQo4/3SRB/NaQWHRSdeXEkyxhdklGSL7az/d/RQqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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