SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '45b500f3dedecdd208097629b8cda8ef646e9315eca56a2b59fc6973abb1de4c' 
  AND token = 'cYbZ+fSHBCKNMhQgqGvgL3qph2yfLFNBxjR9xHKDvrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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