SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd4336a9b98b710f44ef5473de7f977e59821e77848cf529074819f2849ebee5' 
  AND token = 'QkCorzRx0tsjLUrs2gwhYsFVURo0DRrXmV/l5PxmnzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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