SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ad2afbd515a22781e67d357debbcf2430b170e26cb3b7ec3cd0c1295b4cba334' 
  AND token = '2JXSF0ATFSvRLZ0qtp90uvVpBxTUIlOb0u4WR6uo0No=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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