SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'fb754b10cd57c69bc32198248361db14b67b9e59a262f1aa5a56e0e50880f3f4' 
  AND token = '4X4qAVl+NO9lBGxCIrNnTQh/RaQCzwYcYEzmqqiUOAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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