SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f34384a6e73df87bafdcb21f1b1d305eb2630b61c29bb081713afabde994d13' 
  AND token = 'fxgcb2v0NFbTYAlS+Cp06gXBfvYfT1AGv84cXT+/wGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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