SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be4cdcdd32b4b1f0f4d0d6253759ca1bdd060019790603decbfa34748ca65fb2' 
  AND token = 'lL9R+KACH16fnqNQactd+mR2ouQ0UEKvtpls8EoLKMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}