SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12ef1d1a136d0e1540d485f9183179d88e5781c2e0764cb3bf9042db696c5c0a' 
  AND token = 'T7knhpYgJZ/4sLX9cwFEokW7GXg37fMBojX+xLXZTTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}