SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '542a439442ff91cee53d82e129e86de8670b405f6994882c295cfb81ca9cea70' 
  AND token = 'qE9L/G7Dn3w7LqZOmMTsy9OB9sbBWc8ljbIg/nEkU74=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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