SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2eb9a290aabeee66016bc1f5b27f6a020591d1255b223f0878c2887efbe543f' 
  AND token = 'feCWLPHlsU5uQ2Zxd72/qycgUGqJYkiKxucn44gZ9Qc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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