SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6977d14dfb82d56582a11ca13b3a261f728d1e4426209e2765c6f9df1cc1bc7c' 
  AND token = 'AIvYVivnMTDGP+Jo58FqVi2p1zpyXCwLNiJQENu1pLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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