SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c1d8807443eccdd424552f94f508ae0a29e63da667651089f887d4040120f43' 
  AND token = 'dNrPSRvZo25O67mOhIrtvKeLRKKKDGUxd4Wx7Tir4Cg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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