SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '45dd3528ad60b360e081488b07911904607254f9febfd079461006e462e0f4b5' 
  AND token = 'dOIvshaf2CybfqhT4E3g4W2lcGom1wDV/sFdlKZqWtE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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