SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20f13302c0e369124569c03907c4705419670f89b40b34fcdb19d3b23bad2652' 
  AND token = 'pNLGCeH/u0vs4tBDU843RACylRtDgcgOCxoPiHia3UY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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