SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de5823004297f3c9e91d68297061cf572add45b630bdcbb944ed1e84e9e1a2f4' 
  AND token = 'UnWTuamsbYgRJKzAw19dCCUuby6eI4PEMqAnx4AsG0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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