SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e642c218201a042e285642175fbc2a0ad7dd2e6a5099674a1c38fff257b54c15' 
  AND token = '8qa2DGe7Z1hfC91Es38ekK5/dI7GAVIYc3YhZmaqfCo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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