SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83f5e202f8e4a18ae281e56561be6cd72a552092893856b934a867b7bfa52f6e' 
  AND token = 'la43BHlBwrYGVbl8S5dFsvYvcI8zFmNVwWz/LNMjiCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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