SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b34cb2c94263250ebea75471dc3c263a06da466a30c25861c63851c47077d930' 
  AND token = 'Vfu1AXvYmbM5AxpalZXczpR+8/GFaCr4vebCvg8kDXE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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