SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c9be677d3f1069fe2197f61885b5b21893f0fa91d32c198dfc5db66bc1ab250' 
  AND token = 'PKAWV0U7/0qulXwoKY0ykLNh+Jk+bBLuJWYvUJOCr5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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