SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35a65d7f261e14658c7a89a160ab5921e7d14b4589573357ec0fd41029b1ca68' 
  AND token = 'jBEkUsEVb+bKQ6D6HUYWXYpq4jK4vgC0D3mSugj1J3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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