SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5c013767edfc687d421bf5089d79dca44919033a1e61fbb3647ea1d80561c49' 
  AND token = 'oi9E4gLu44xcIz4kONhmpHt6ZSxAc3+ILQSWTIdL7UI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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