SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '87590d8351c061150408f5df276fd82b5440691067aac83ec063e09086dc78be' 
  AND token = '/Zr4jxxZlKqhFmtTL1YozuCLYDeZrnQcKXtwZHnjcNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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